The present invention is directed to an improvement in a pneumatic installation which supplies a desired fluid pressure through an outlet flow passage of a fluid pressure distribution network. The improvement consists of having a pneumatic device having a compressed fluid feed inlet which branches into two opposed recompression chambers. There is a two part piston located within the two opposed recompression chambers for reciprocatingly moving therein, each part of the piston having other independent opposed thrust chambers located in its sleeve so that when one of these chambers is activated, i.e. receiving fluid, the other is inoperative.
The described opposed recompression and thrust chambers are controlled by a common distributor, the automatic activation of which is determined by end of stroke valves which are located in the opposed recompression chambers of the two part piston and serve to connect the compressed fluid feed inlet to the front of the recompression chamber which has the back enclosed by a wall or stem of the two part piston which connects the two parts of the piston and separates the opposed recompression chambers from each other. The end of stroke valves additionally serve to connect the compressed fluid feed inlet to a conduit.
The distributor connected to the exterior is composed of a conventional five way chamber which connects two passages or ports to each one of the chambers on the same side, one of the passages or ports being a control conduit and the other a thrust flow passage.
The thrust flow passage branches, in turn, into two passages, one of which has a smaller cross section and is provided with a unidirectional valve which leads to the recompression chamber, while the other passage is free and leads to the thrust chamber.
The distributor is likewise provided with ports for evacuating the contents of the inoperative thrust chamber, while each one of the recompression chambers is provided with corresponding outlet conduits which corporate a unidirectional valve, the two conduits of the described recompression chambers being joined at a common outlet which also makes up the outlet passage for recompression air.
With the previously described improvements, there is arranged at the base of the pneumatic machine a compressed fluid tank wherein the fluid is kept at a constant pressure thus eliminating the requirement of having to place a pressurized fluid supply for the tank near to the machine in operation and thus the tank in combination with the pneumatic device is, in effect, a compressed air generator. Therefore, the object of this invention is to supply pressurized fluid for use in mining operations, specifically in galleries, since it does not consume atmospheric air and is, in addition, explosionproof.
However, it has been shown in practice that the end of stroke valves which cause the recompression cyclic action, are subject to breakdown and are even prematurely activated when, due to the wear on the springs, they are compressed by the pressure reached in the recompression chamber.